For the industrial production of fluid mixtures, such as beverages or suspensions, consisting of two or more fluid components, a first and a second fluid are often made to flow from two separate fluid lines conducting the two fluids separately into a fluid line forwarding the two fluids together.
The mixing ratio of such a fluid mixture of predeterminable mass or predeterminable volume to be produced by mixing a first fluid, held in a first fluid line, and a second fluid, held in a second fluid line, is commonly set with the aid of a ratio control system. A process implementing such ratio control commonly comprises the steps of:                causing the first fluid to flow into a third fluid line, connected at least intermittently to the first fluid line, in accordance with a predeterminable set point for a volumetric or mass flow rate of the first fluid;        causing the second fluid to flow into the third fluid line, which is also at least intermittently connected to the second fluid line;        measuring the volumetric or mass flow rate of the first fluid and generating a first measurement signal, which represents the measured flow rate of the first fluid;        measuring a totalized volumetric or mass flow rate of the first fluid and generating a first measured flow rate value, which represents the totalized flow rate of the first fluid; and        determining an instantaneous set point for a totalized volumetric or mass flow rate of the second fluid based on the set point for a volumetric or mass flow rate of the first fluid and/or on the first measured flow rate value.        